That's a solid base for a top down shooter, it has a lot of little imperfections but it's overall quite fun to play ! The upgrade system with health and sanity is pretty interesting !
I think there are lots of little things that make the game a bit clunky, which is normal for a jam game. I'll try to list what I think could improve it substantially :
- The atmosphere is great, but it's a bit dark currently. Making it a bit brighter would have made the levels more interesting to explore imo
- The bullets are way too big to be dodgeable, which is the whole point of the bullet hell genre. When more than two enemies are there, the only option is to hide behind an obstacle to not take damage.
- the enemies see you instantly, and run at you right away, which makes the level design a bit useless. Maybe making some of them stay in place and shoot when they see the player could improve that without adding too much ai work
- I found the rooms a bit too small for the gameplay, I kept hitting small obstacles when trying to move during fights (the fact that the obstacles are dark might be a factor too)
Good job, that's a really solid entry, keep practicing and you'll make amazing games !